Thermodynamic parameters for the interaction between etidronic acid and inorganic and organic mercury(II)

The dependence of the stability constants on ionic strength, studied through a Debye-Hückel type equation, is also reported. To enrich the thermodynamic study, the enthalpy values of the complex species were obtained by calorimetric titrations at I = 0.1 mol·L−1 in NaCl and T = 298.15 K. Finally, the sequestering ability of HEDPA towards Hg2+ and CH3Hg+ was calculated by means of an empirical parameter, known as pL0.5, under blood (I = 0.1 mol·L−1, pH = 7.4, T = 310.15 K) and sea water (I = 0.7 mol·L−1, pH = 8.1, T = 298.15 K) conditions. pL0.5 represents the total ligand concentration required to sequester the 50% of a metal cation present as traces.